Data from: On the accuracy of paleodiversity reconstructions: a case study in Antarctic Neogene radiolarians

The deep-sea Cenozoic planktonic microfossil record has the unique characteristics of continuously well-preserved populations of most species, with virtually unlimited sample size, and therefore constitutes, in principle, a major resource for macroevolutionary research. Antarctic Neogene radiolarians in particular, are diverse, abundant and consistently well-preserved and evolved rapidly. This fauna is, in theory, a near-perfect testing ground for paleodiversity reconstructions. In this study we determined the diversity history of these faunas from a new quantitative, taxonomically complete data set from Neogene and Quaternary sections at several Antarctic sites. The pattern retrieved by our whole-fauna data set shows a significant, largely extinctionless ecological change in faunal composition and decrease in the evenness of species' abundances during the late Miocene, followed 3 Myr later, at around 5 Ma, by a significant drop in diversity. We tentatively associate this ecological event with a synchronous, regional change in the composition of the primary producers, but as yet cannot identify any environmental changes associated with the later extinction. Further, our whole-fauna diversity history was compared to diversity computed from much less complete, biostratigraphically oriented studies of species' occurrences, compiled in the Neptune database and reconstructed by using subsampling methodologies. Comparison of our whole-fauna and subsampling-reconstructed diversity patterns shows that the first-order trends are the same in both, suggesting that, to some degree, such literature compilations can be used to explore diversity history of plankton. However, our results also highlight substantial errors and distortions in the reconstructed diversity which make it poorly suited to more-detailed studies (e.g., for comparison of diversity history with paleoenvironmental history). We conclude that detailed studies of plankton diversity, and particularly those attempting to understand the relation between diversity and paleoceanographic change, should be based on taxonomically comprehensive, quantitative data.深海新生代浮游微体化石记录具备独特优势：绝大多数物种种群保存连续完好，样本量近乎无限，因此原则上成为宏演化研究的重要资源。其中以南极新近纪放射虫最为突出，其类群多样、数量丰富且保存稳定，演化速率较快，该动物群理论上是古生物多样性重建的近乎完美的试验场。本研究依托多个南极站点新近纪与第四纪剖面的全新定量、分类学完整数据集，重建了这类动物群的多样性演化历史。全动物群数据集揭示的演化模式显示：晚中新世时期，动物群组成发生了显著且基本无灭绝事件的生态转变，同时物种丰度均匀度出现下降；在该转变发生300万年后，即约5 Ma时，多样性出现显著下降。我们初步将这一生态事件与初级生产者组成的区域性同步变化相关联，但目前尚未明确与此次后期灭绝事件相关的环境变化。此外，我们将全动物群的多样性演化历史，与基于海王星（Neptune）数据库汇编的、远不够完整的生物地层学导向型物种出现记录，通过子采样方法重建得到的多样性数据进行了对比。对比全动物群数据集与子采样重建的多样性模式可见，二者的一级演化趋势一致，这表明此类文献汇编在一定程度上可用于探索浮游生物的多样性演化历史。不过，我们的研究结果也揭示了重建多样性数据中存在的显著误差与失真，使其难以适用于更细致的研究，例如将多样性演化历史与古海洋环境变化进行对比分析。我们认为，针对浮游生物多样性的详细研究，尤其是旨在阐明多样性与古海洋环境变化之间关联的研究，应基于分类学全面的定量数据集。